antigenic and s-1 genomic characterization of the delaware variant serotype of infectious bronchitis virus.a previously unrecognized infectious bronchitis virus (ibv) serotype, referred to hereafter as the delaware variant (de var), was isolated from commercial broiler chickens during a severe, widespread respiratory disease epornitic in the delmarva peninsula region of the united states in january-march 1992. the de var serotype was found to be antigenically unrelated by virus-neutralization (vn) test to nine reference ibv serotypes from north america. additional vn tests indicated that the de var i ...19979356713
sequence comparisons of the variable vp2 region of eight infectious bursal disease virus isolates.the vp2 gene is part of the genomic segment a of infectious bursal disease virus (ibdv). it has been identified as the major host-protective antigen of ibdv and is known to contain conformationally dependent protective epitopes. a 643-base pair segment covering the hypervariable region of this gene from three recent serologic variant ibdv isolates from the southeastern united states, two variants from the delmarva peninsula, and three serologic standard viruses were amplified and sequenced using ...19979087318
antigenic characterization of an arkansas isolate of infectious bursal disease virus.the s977 strain of infectious bursal disease virus (ibdv) was isolated in northwest arkansas in 1977 from the bursae of young broilers with high maternal antibody titers to the moulthrop strain of ibdv (bursavac). the comparison of a plaque-purified isolate of s977 with other ibdv serotype 1 and serotype 2 strains using virus neutralization indicates that s977 is a subtype of serotype 1 vaccine viruses and the md variant strain of ibdv and has no relatedness to the delaware variant a (vara) viru ...19968883789
pathogenicity studies of an arkansas variant infectious bursal disease virus.a variant infectious bursal disease virus (ibdv), ibdv-s977, was blind passaged in cell culture, plaque purified, and attenuated by serial passage at a high multiplicity of infection (moi) in chick embryo fibroblasts (cef). cell culture passages of virus caused less bursal atrophy and splenomegaly than did the original isolate and retained immunogenicity; however, virus tended to persist for a longer time in the bursa and spleen of birds infected with the highest cef passages. antibody to both l ...19968883779
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